Hybrid constant/variable frequency starter drive

Abstract

A power generation system and method uses a constant frequency generator to generate electrical power in a generate mode. When operating in a start mode, the constant frequency generator is controlled by a motor controller which at least partially controls another component while the system is in a generate mode. The power generation system and method can be implemented in, for example, an aircraft electrical architecture.

1. A generation system comprising:
 a constant frequency generator for taking rotation from a rotating member and generating power having a constant frequency; and 
 a motor controller connected to said constant frequency generator, when said constant frequency generator is in a start mode, and connected to a second component when said constant frequency generator is in a generate mode. 
 
     
     
       2. The generation system of  claim 1 , wherein said constant frequency generator comprises a start clutch. 
     
     
       3. The generation system of  claim 1 , additionally comprising a switch connecting said motor controller to said constant frequency generator in a first position and connecting said motor controller to said second component in a second position. 
     
     
       4. The generation system of  claim 1 , wherein said second component comprises a variable frequency generator. 
     
     
       5. The generation system of  claim 1 , wherein said motor controller is disconnected from said constant frequency generator in said generate mode. 
     
     
       6. An aircraft electrical architecture comprising:
 at least one gas turbine engine, said gas turbine engine having a shaft and being associated with a constant frequency generator; 
 said constant frequency generator being operable to take rotation of said shaft and generating power having a constant frequency in a generate mode, and operable to accept power and generate rotation of said shaft in a start mode; and 
 a motor controller connected to said constant frequency generator in said start mode, said motor controller connected to a second component in said generate mode. 
 
     
     
       7. The aircraft electrical architecture of  claim 6 , wherein said constant frequency generator comprises a start clutch. 
     
     
       8. The aircraft electrical architecture of  claim 6 , additionally comprising a switch connecting said motor controller to said constant frequency generator in said start mode, and connecting said motor controller to said second component in said generate mode. 
     
     
       9. The aircraft electrical architecture of  claim 6 , wherein said second component comprises a variable frequency generator. 
     
     
       10. The aircraft electrical architecture of  claim 6 , wherein said motor controller is disconnected from said constant frequency generator in said generate mode. 
     
     
       11. A method for controlling a constant frequency generator comprising the steps of:
 connecting a motor controller to a constant frequency generator when said constant frequency generator enters a start mode; 
 supplying electrical power to said constant frequency generator; 
 engaging a start clutch when rotation of a rotor in said constant frequency generator exceeds a preset threshold; and 
 disconnecting said motor controller from said constant frequency generator and connecting said motor controller to a second component when said constant frequency generator enters a generate mode. 
 
     
     
       12. The method of  claim 11 , wherein said step of disconnecting said motor controller from said constant frequency generator and connecting said motor controller to a second component comprises toggling a switch from a first switch mode to a second switch mode, said switch connecting said motor controller to said constant frequency generator in a first switch mode, and said switch connecting said motor controller to said second component in a second switch mode. 
     
     
       13. The method of  claim 11 , wherein said second component comprises a variable frequency motor.